A Fall of Light is a standalone and considered outside the Effects series because it's a M/M romance that deviates from the conventions in the Effects series - namely, it's not a first-person, dual POV. Those who have read the Effects series may recall that Greg Van De Meer plays a supporting but critical role in Sound Effects. That said, you don't need to have read any of the Effects series to enjoy A Fall of Light. But if you're interested, chronologically, it takes place after Ripple Effects and before Aftereffects.
A Fall of Light (M/M)
The Effects Series (M/F)
The Effects series is a collection of novels that can each be read as a standalone. Readers can easily come into the series at any point and enjoy each book as a complete story.
If you enjoy acquaintances-to-lovers: Ripple Effects
If you enjoy strangers-to-lovers: Sound Effects
If you enjoy friends-to-lovers: Aftereffects
If you enjoy enemies-to-lovers: Side Effects
Having said that, the books are connected so there will be very mild spoilers if you read them in random order.
If you want to avoid spoilers altogether (even the very mild ones), Ripple Effects and Sound Effects are interchangeable as a starting point. Ripple Effects was the first book written in the series, telling the story of Danny and Sarah. It introduces many of the characters in the Effects series. Sound Effects then takes an eleven-year step back in time to tell Jamie and Mel’s story, which is referenced in Ripple Effects. Chronologically, Sound Effects is the first book in the series, and also features a younger version of Danny (still in his dreaded cologne phase!).
Either way, you can’t go wrong if you begin with one of these two.
The third book, Aftereffects, is Keir and Selene’s story, and chronologically takes place a couple of years after Ripple Effects. Selene is a bit older now, and trying to make a name for herself as a graphic artist, when she rear-ends Keir on the Golden Gate Bridge. Danny, Sarah, Jamie, and Mel all make appearances.
And finally, Side Effects is Marcus’s story. We first meet him in Ripple Effects as a 21-year-old prickly boy-genius. In Side Effects, he’s four years older, now the founder of an indie gaming studio (thus, the slightly different cover art!), and no less prickly for the passage of time.
Side Effects contains an epilogue for the whole series, bringing all of these characters and stories together for one final glimpse into lives well lived.